<!DOCTYPE html>
<html lang='en'>
<head>
    <meta charset='UTF-8'>
    <title>下文规则 1 - 3</title>
</head>
<body>
    <script>
        function fun() {
            console.log(this.a + this.b);
        }
        let obj = {
            a: 1,
            b: 2,
            c:[{
                a: 3,
                b: 4,
                c: fun
            }]
        };

        let a = 5;
        obj.c[0].c();
    </script>
</body>
</html>
